Ensuring That Your Silverlight 2 or
Silverlight 3 Beta Applications Work
with the Silverlight 3 Release
1 Introduction
This topic discusses the changes made to the Silverlight runtime and Silverlight tools
between Silverlight 2 and Silverlight 3. The changes discussed in this topic are
focused on changes that might cause your older Silverlight-based applications to now
fail or behave differently, not on new features/enhancements for this release. This
topic has three primary sections:
1. Breaking Changes since Silverlight 3 Beta: The changes described in this
section could potentially break applications written for Silverlight 3 Beta.
2. Breaking Changes since Silverlight 2: The changes described in this section
could potentially break applications written for Silverlight 2.
3. Upgrade Breaking Changes. These changes will not break Silverlight 2
applications unless you re-compile using Silverlight 3.
Note
Corrections/Additions to this topic (if any) are listed here.
2 Table of Contents
1
Introduction ............................................................................................... 1
2
Table of Contents ....................................................................................... 1
3
Breaking Changes since Silverlight 3 Beta ...................................................... 4
3.1
DockPanel, WrapPanel, Expander, HeaderedContentControl, Viewbox,
DataForm moved to the Silverlight Toolkit ........................................................ 4
3.2
AutoCompleteBox: Search -> Filter ........................................................ 5
3.3
New template part for AutoCompleteBox: “Selector”, typeof(Selector) ....... 5
3.4
AutoCompleteBox.TryGetSelectionAdapter(object o) is now
GetSelectionAdapterPart() .............................................................................. 5
3.5
AutoCompleteBox: The “DropDownToggle” template part of type
ToggleButton has been removed ..................................................................... 6
3.6
DataGrid RowGroupExpanding and RowGroupCollapsing events removed .... 7
3.7
DataGrid.SortDescriptions and GroupDescriptions properties removed ........ 7
3.8
DataGrid Entity level validation errors are shown using a ValidationSummary
instead of a ListBox ....................................................................................... 7
3.9
DataGrid no longer selects the first item by default .................................. 8
3.10
DataForm Changes ............................................................................... 8
3.11
Breaking Changes to System.ComponentModel.dll and the DataPager ...... 10
1
3.12
PagedCollectionView ........................................................................... 10
3.13
DataPagerAutomationPeer................................................................... 10
3.14
BindableAttribute and BindingDirection have been removed .................... 11
3.15
Changes to ValidationAttribute............................................................. 11
3.16
Signatures for [CustomValidation] methods have changed ...................... 12
3.17
Frame only supports navigating to Pages .............................................. 13
3.18
Frame breaking change related to UriMapper ......................................... 13
3.19
Effects Files (.ps) can no longer be loaded as Content ............................ 14
3.20
WritableBitmap constructor parameter removed .................................... 14
3.21
RenderOptions.TextRenderingOptions is now TextOptions.TextHintingMode
15
3.22
Transparent platform extensions are not hosted on Microsoft.com............ 15
3.23
Out-of-browser API name changes ....................................................... 15
3.24
ExecutionStates.DetachedUpdatesAvailable is removed .......................... 16
3.25
Icon.Size type change and <Icon Size=”…”> format changed .................. 17
3.26 XmlConvert.IsNCNameSurrogatePair() and IsStartNCNameSurrogatePair()
have been removed ..................................................................................... 17
3.27
SaveFileDialog.File -> SaveFileDialog.SafeFileName ............................... 17
3.28
WriteableBitmap[] is now WritableBitmap.Pixels[] .................................. 18
3.29 WriteableBitmap.Lock() and Unlock() have been removed; calling
Invalidate() is now required .......................................................................... 18
4
Breaking Changes since Silverlight 2 ........................................................... 18
4.1
System.Web.Silverlight.dll has been removed from the SDK .................... 19
4.2
Silverlight Applications now respond to Browser Zoom ............................ 20
4.3
Popup Tab key Change ....................................................................... 20
4.4
ComboBox Popup Clipping Fixed .......................................................... 20
4.5
Silverlight always redraws Popups when PopupRenderTransform changes . 21
4.6
ContentPresenter.Content = "string" no longer changes the
ContentTemplate property ............................................................................ 21
4.7
ContentControl now ignores Content when using an empty ContentTemplate
21
4.8
Setting ContentControl.Content does not cause unnecessary
OnApplyTemplate calls ................................................................................. 22
4.9
ComboBox and ContentControl now displays strings rather than numbers
when ItemsSource is set to enum with typeconverter ...................................... 22
4.10
item
ComboBox with no selected item takes an extra keystroke to select second
22
2
4.11 HorizontalScrollBarVisibility and VerticalScrollBarVisibility can now be set in
a style for ComboBox and ListBox.................................................................. 22
4.12
ListBoxItem.HorizontalContentAlignment is now respected ...................... 22
4.13
ListBoxItem.Style now takes precedence over ListBox.ItemContainerStyle 22
4.14 Tabbing inside a ListBox now moves focus to next control rather than next
ListBox Item ............................................................................................... 23
4.15
Removed TemplatePart declarations from PasswordBox/TextBox ............. 23
4.16 TextAlignment in TextBox now works relative to the document instead of the
TextBox ..................................................................................................... 23
4.17
Default colors for read-only TextBoxes have changed ............................. 23
4.18 ENTER key will now respects Button.ClickMode which defaults to Release
(KeyUp) ..................................................................................................... 24
4.19
Slider control's hit test area now matches what is visible ........................ 24
4.20 Malformed URLs inside clientaccesspolicy.xml now cause that URL to be
ignored, not the rest of the file ...................................................................... 24
5
4.21
Bug fix where changing Opacity did not always redraw ........................... 24
4.22
DataBinding requires property setter to be public ................................... 24
4.23
Changing Binding.Path after SetBinding() is not allowed ......................... 24
Upgrade Breaking Changes ........................................................................ 25
5.1
OpenFileDialog.ShowDialog() can now only be opened from a user initiated
event 26
5.2
Tabbing processing and associated callbacks changed from asynchronous to
synchronous ............................................................................................... 26
5.3
Mouse events inside a Popup now give positions relative to the pop-up not
the entire application ................................................................................... 26
5.4
Popup can now only have one parent ................................................... 27
5.5
Namescopes inside Popup now work correctly ........................................ 27
5.6
FindElementsInHostCoordinates now searches Popup's ........................... 27
5.7
Removed extra events associated with replacing Item in ItemsControl ..... 27
5.8
ScrollViewer now clamps scrollbar positions to
ScrollableWidth/ScrollableHeight ................................................................... 27
5.9
Rectangle and Ellipse now appear when Stretch is set and Height and/or
Width are not set ........................................................................................ 27
5.10
Width of TextBlock, TextBox, and PasswordBox now rounded up .............. 28
5.11
textblock.FontFamily = null throws ArgumentNullException ..................... 28
5.12
Spaces no longer rendered between Run elements within template .......... 28
5.13
RadioButton.GroupName now searches outside template for RadioButtons 28
5.14
ComboBox content now gets IsHitTestVisible="false" ............................. 28
5.15
TextBox now respects the Opacity property ........................................... 28
3
5.16 FrameworkElementAutomationPeer ctor with null parameter throws
NullReferenceException ................................................................................ 29
5.17 HyperlinkButton now navigates the entire window and not just the IFRAME
that Silverlight is in ..................................................................................... 29
5.18 Correct base URI used when Silverlight v2+ application does not have XAP
file extension .............................................................................................. 29
5.19 Application.Current.Host.Source now returns an absolute URL even when
.xap URL has a query string .......................................................................... 29
5.20
ResourceDictionary enum bug fixed ...................................................... 29
5.21 ReadOnlyObservableCollection moved from
System.Windows.Controls.Data.dll to System.Windows.dll ................................ 30
5.22
DataGridEndingEditEventArgs was removed from the SDK ...................... 30
5.23
PollingDuplexHttpBinding Changes ....................................................... 30
5.24
Bug fix with removing event handlers ................................................... 30
5.25
Bug fix allowing <Cursors> instead of <Cursor>.................................... 30
5.26
Custom attached properties in XAML require xmlns are prefixed .............. 30
5.27
Bug fix where subclass control could load wrong resource ....................... 31
5.28
null
Bug fix where ValueConverter is not called when leaf object on the path is
31
5.29 Thumb control now calculates drag relative to the absolute position rather
than relative to its parent ............................................................................. 31
5.30
Setting Binding properties after SetBinding() no longer supported............ 31
5.31
Child of a ContentPresenter can now only have one parent ...................... 32
5.32 Relative URLs pointing to resources outside the .xap are now relative to the
.xap file not the HTML page .......................................................................... 32
5.33
Silverlight 3 automatically displays validation errors ............................... 32
5.34
Image.Source and ImageBrush.Source now return null when not initialized
33
3 Breaking Changes since Silverlight 3 Beta
3.1 DockPanel, WrapPanel, Expander,
HeaderedContentControl, Viewbox, DataForm
moved to the Silverlight Toolkit
The following controls and types have been removed from the Silverlight SDK:
 DockPanel
 WrapPanel
 Expander
 HeaderedContentControl
 Viewbox
4





DataForm
ExpandDirection
ExpanderAutomationPeer
LengthConverter
StretchDirection
They are now in the Silverlight Toolkit, which is available from
http://www.codeplex.com/Silverlight.
3.2 AutoCompleteBox: Search -> Filter



AutoCompleteBox.SearchMode property is now AutoCompleteBox.FilterMode
AutoCompleteSearchMode enum is now AutoCompleteFilterMode
AutoCompleteSearchPredicate delegate is now AutoCompleteFilterPredicate
Prior to this change:
<input:AutoCompleteBox SearchMode=”Contains” />
After the change:
<input:AutoCompleteBox FilterMode=”Contains” />
3.3 New template part for AutoCompleteBox:
“Selector”, typeof(Selector)
If you have a AutoCompleteBox control template with a part named
“SelectionAdapter”, you should rename it to “Selector”.
Previously, AutoCompleteBox would grab any template part named
‘SelectionAdapter’, and attempt to either use it as an adapter, or wrap it in a predefined SelectorSelectionAdapter.
With this change, the basic logic to prepare the Selection Adapter for the
AutoCompleteBox is:
 Find a template part named ‘Selector’.
o If the control implements ISelectionAdapter, use it.
o Else, if a Selector was found, create a new SelectorSelectionAdapter for
it.
 If no SelectionAdapter has been prepared, locate a template part named
SelectionAdapter.
3.4 AutoCompleteBox.TryGetSelectionAdapter(object
o) is now GetSelectionAdapterPart()
Previously, the AutoCompleteBox API contained a protected virtual method named
“TryGetSelectionAdapter.” The API did not actually implement the TryGet pattern.
The new API is simply a protected virtual method with no parameters named
GetSelectionAdapterPart.
5
3.5 AutoCompleteBox: The “DropDownToggle”
template part of type ToggleButton has been
removed
The default control template for AutoCompleteBox never has made use of this
template part. To improve the templating experience in Blend, this template part
has been removed.
How do I update an existing application?
In the file with the custom control template definition, add a Click event handler in
XAML and code behind. Then, locate the auto complete control in the visual tree
hierarchy and toggle its IsDropDownOpen dependency property.
Anyone who derived from AutoCompleteBox should still be able to define their own
ToggleButton template part and flip the IsDropDownOpen property.
From an updated sample application, here is part of the custom control template:
Before (XAML)
<ToggleButton x:Name="DropDownToggle"
Style="{StaticResource
ComboToggleButton}" />
After (XAML)
<ToggleButton x:Name="DropDownToggle"
Style="{StaticResource
ComboToggleButton}"
Click=”DropDownToggle_Click”
/> …
And the code behind file:
Before (C#)
(n/a)
After (C#)
private void DropDownToggle_Click(object sender,
RoutedEventArgs e)
{
FrameworkElement fe = sender as FrameworkElement;
AutoCompleteBox acb = null;
while (fe != null && acb == null)
{
fe = VisualTreeHelper.GetParent(fe) as
FrameworkElement;
acb = fe as AutoCompleteBox;
}
if (acb != null)
{
acb.IsDropDownOpen = ! acb.IsDropDownOpen;
}
}
6
3.6 DataGrid RowGroupExpanding and
RowGroupCollapsing events removed
These events did not completely work in the Beta, and have been removed.
3.7 DataGrid.SortDescriptions and GroupDescriptions
properties removed
The SortDescriptions and GroupDescriptions properties were removed from
DataGrid. You can use the code behind to setup the group descriptions.
Silverlight 3 Beta
[Xaml]
<dataGrid.GroupDescriptions>
<windata:PropertyGroupDescription PropertyName=”State” />
</dataGrid.GroupDescriptions>
Silverlight 3 RTM
[c#]
pagedCollectionView.GroupDescriptions.Add(new
PropertyGroupDescription(“State”));
3.8 DataGrid Entity level validation errors are shown
using a ValidationSummary instead of a ListBox
Who Is Affected: Silverlight 3 Beta managed applications that re-templated the
DataGrid to a custom template that includes a ListBox for validation errors.
Summary: To have a standard look and feel for entity level validation errors, the
DataGrid now uses a ValidationSummary similar to the DataForm. Previously, the
DataGrid used a ListBox.
Fix Required: Users with custom DataGrid templates that include a ListBox for
validation errors need to update their templates.
Silverlight 3 Beta
[Xaml]
<ListBox Name="ErrorsListBox" Grid.Row="3" Grid.ColumnSpan="3" MaxHeight="91"
Background="#FFEFEFEA" BorderThickness="0,1,0,0">
…
Silverlight 3 RTM
7
[Xaml]
<dataInput:ValidationSummary Name="ValidationSummary" Filter="ObjectErrors"
Grid.Row="3" Grid.ColumnSpan="3" MaxHeight="90"/>
3.9 DataGrid no longer selects the first item by default
Who Is Affected: Silverlight 2 applications that depend on the DataGrid selecting
the first item by default.
Summary
Based on customer feedback, the DataGrid no longer selects the first item by default,
which also matches that of other list based controls like the ListBox. Now, the
DataGrid’s current item is by default the first item, but that item is not selected.
Tabbing in to the DataGrid causes the current item to be selected. The DataGrid will,
however, select the an ICollectionView’s current item by default if its ItemsSource is
set to an ICollectionView implementation. This is consistent with the ListBox and
consistent with other consumers of ICollectionView, and it also supports the
master/details scenario via CollectionView.
Fix Required
Silverlight 2 users depending on the DataGrid to select the first item by default now
need to explicitly set the SelectedItem or the SelectedIndex after setting the
ItemsSource.
3.10 DataForm Changes
The largest change related to DataForm impacts anyone using the Fields collection
in the DataForm, and is as follows:
DataFormFields have all been removed and DataForm.Fields collection has been
removed. They have been replaced with the new DataField control, which is a
control that wraps content with a label and DescriptionViewer. Also, note that you
must now explicitly specify Mode=TwoWay on bindings in the DataField, whereas
before you could just specify the path and the DataFormField would inject TwoWay
into the binding. For example, if you have the following in the Fields collection:
<dataControls:DataFormTextField Binding="{Binding FirstName}" />
...you would want to instead place this in the EditTemplate:
<dataControls:DataField>
<TextBox Text="{Binding FirstName, Mode=TwoWay}" />
</dataControls:DataField>
8
Note that since these are now controls, DataFormFieldGroups can be replaced just
with regular panels.
Also note that since these are now controls unto themselves, the DataForm no
longer handles all of the alignment of the labels in these fields. The DataForm will
group these fields together at the top level, but if you want more fine-tuned
grouping (for example, two columns of fields), you can use the attached property
DataField.IsFieldGroup on a Panel to specify that the DataFields within the
Panel should have their labels grouped together in width. The following shows an
example:
<StackPanel Orientation="Horizontal">
<StackPanel dataControls:DataField.IsFieldGroup="True">
<dataControls:DataField>
<TextBox Text="{Binding FirstName, Mode=TwoWay}" />
</dataControls:DataField>
<dataControls:DataField>
<TextBox Text="{Binding LastName, Mode=TwoWay}" />
</dataControls:DataField>
</StackPanel>
<StackPanel dataControls:DataField.IsFieldGroup="True">
<dataControls:DataField>
<TextBox Text="{Binding StreetAddress, Mode=TwoWay}" />
</dataControls:DataField>
<dataControls:DataField>
<TextBox Text="{Binding State, Mode=TwoWay}" />
</dataControls:DataField>
</StackPanel>
</StackPanel>
This would cause the FirstName/LastName DataFields to have their labels the same
width, and similarly for StreetAddress/State DataFields.
That represents the bulk of this breaking change. In addition, there are other
breaking changes on the DataForm which are as follows:



FieldEditEnding and FieldEditEnded have been removed.
GetFieldElement() has been removed.
ItemEditEnding, ItemEditEnded, CommitItemEdit() have been changed
to EditEnding, EditEnded, and CommitEdit() respectively.
9






CanMoveToXXXXItem have been removed, as they can be derived from the
collection given to the DataForm.
CanUserAdd/DeleteItems have been removed, as they are implied through
CommandButtonsVisibility.
IsEditing and IsAddingItem have been removed, as they are implied
through Mode.
FieldLabelPosition and FieldLabelStyle have become LabelPosition and
LabelStyle.
WrapAfter and Orientation have been removed.
The type names DataFormFieldLabelPosition and
DataFormDescriptionViewerPosition have been changed to
DataFieldLabelPosition and DataFieldDescriptionViewerPosition.
3.11 Breaking Changes to System.ComponentModel.dll
and the DataPager
These breaking changes are summarized below:
1. System.ComponentModel.dll has been deleted.
2. From System.ComponentModel, the following classes/interfaces have been
moved to the new System.Windows.Data.dll (namespaces have remained
unchanged)
a. PagedCollectionView
b. CollectionViewGroup
c. IEditableCollectionView
d. IPagedCollectionView
e. PageChangingEventArgs
f. PropertyGroupDescription
3. The following classes/interfaces will no longer be part of the SDK
a. EntityAction
b. IEditableCollection
c. IIndexableCollection
4. IPagedCollection has been removed. PagedCollectionView no longer has
special-cases implementers of IPagedCollection.
5. DataPager.Source is no longer of type IPagedCollectionView, but is now
an IEnumerable that may also be an IPagedCollectionView. When nonIPagedCollectionViews are given to the DataPager, it behaves as though a
collection with a single large page was bound to the control. To invoke
IPagedCollectoinView APIs, cast the Source property to an
IPagedCollectionView.
3.12 PagedCollectionView
PagedCollectionView no longer supports arbitrary remote paging. As a result,
PagedCollectionView.NewItemPlaceholder has been removed, and
PagedCollectionView.ItemCount and TotalItemCount properties are now read-only.
3.13 DataPagerAutomationPeer
The DataPagerAutomationPeer now implements IRangeValueProvider explicitly rather
than implicitly. As a result, the following members have been removed from the
DataPagerAutomationPeer class:
public bool IsReadOnly { get; set; }
10
public
public
public
public
public
public
double LargeChange { get; set; }
double Maximum { get; set; }
double Minimum { get; set; }
double SmallChange { get; }
double Value { get; }
void SetValue(double value);
3.14 BindableAttribute and BindingDirection have been
removed
In Silverlight 3 Beta, the Bindable attribute was used to annotate the properties of a
business object allowing the UI to react in two ways:

To treat the property as read only in the UI.

To tell controls that perform auto-generation, such as DataGrid and
DataForm, if they should generate UI for the property.
In the Silverlight 3 release, the Editable and Display attributes should be used for
these purposes.
Marking a property as ReadOnly in the UI:
Before
[Bindable (true,
BindingDirection.OneWay)]
public string foo {get;set;}
After
[Editable (false)]
public string foo {get;set;}
Marking a property to not have controls auto-generate UI for it:
Before
[Bindable (false)]
public int bar {get;set;}
After
[Display (AutoGenerateField=false)]
public int bar {get;set;}
3.15 Changes to ValidationAttribute
Any classes that derive from the Beta of ValidationAttribute will likely need to be
updated. Instead of returning a bool from IsValid, implementations should only
override the ValidationContext-based IsValid method and return ValidationResult.
ValidationContext can be ignored if it is not needed.
The ValidationAttribute API has been changed to the following:
public abstract class ValidationAttribute: Attribute {
public void Validate(object value, string name);
public void Validate(object value, ValidationContext validationContext);
public bool TryValidate(object value, ValidationContext validationContext,
ref ValidationResult validationResult);
public ValidationResult GetValidationResult(object value,
ValidationContext validationContext, out ValidationResult validationResult);
11
public abstract bool IsValid(object value);
protected virtual bool ValidationResult IsValid(object value,
ValidationContext validationContext, out ValidationResult validationResult);
}
Representing Success and Failure: ValidationAttribute implementations need to
return ValidationResult to represent both success and failure. In order to represent
success, public static readonly ValidationResult Success was added to
ValidationResult. For failure scenarios, ValidationResult has two constructors for
providing an error message and optionally a list of member names. These
constructors did not change, but the Success field was an addition.
Here is a very simple implementation of a ValidationAttribute, illustrating both
success and failure.
public class IsTrueAttribute : ValidationAttribute {
protected override ValidationResult IsValid(object value,
ValidationContext validationContext) {
if (value is bool && (bool)value) {
return ValidationResult.Success;
}
else {
return new ValidationResult("The value provided was not
true");
}
}
}
The Validator class was updated to call GetValidationResult instead of TryValidate.
Anything else that was calling TryValidate will also need to be updated, although
there is no other framework code affected by this change.
3.16 Signatures for [CustomValidation] methods have
changed
Anywhere that a custom validation method was implemented, the signature will have
to be updated. Conflicts will not be discoverable at runtime. If you have
implemented any custom validation methods, you must find those implementations
and update the method signatures to match one of the new supported signatures.
CustomValidationAttribute is used to provide a Type and a Method to invoke for
validation. This is a simple mechanism for extending the validation framework to call
custom validation routines, which uses a convention for the method signatures so
that the referenced method can be called.
12
In Silverlight 3 Beta, [CustomValidation] attributes required one of the following
method signatures:
public static bool MethodName([type] value) {…}
public static bool MethodName([type] value, ValidationContext context, out
ValidationResult result) {…}
In the final version of Silverlight 3, the supported method signatures have been
changed to the following:
public static ValidationResult MethodName([type] value) {…}
public static ValidationResult MethodName([type] value, ValidationContext
context) {…}
The return type has changed, and the "out ValidationResult" parameter has been
removed.
3.17 Frame only supports navigating to Pages
Frame only supports navigation to XAML for controls derived from Page. Attempts to
navigate to items other than pages will result in an exception.
In Silverlight 3 Beta, it was possible to navigate to XAML for a UserControl, which
increased complexity and required users to know how to reach the Navigation service
to get navigation-related information within that UserControl. If this is still
necessary, wrap the UserControl in a Page or use a Page as the parent class.
3.18 Frame breaking change related to UriMapper
Previously, the way to provide a UriMapper to a Frame control was by adding it as a
resource with a key of “uriMapper”:
Prior to this change:
<navigation:Frame.Resources>
<nav:UriMapper x:Key=”uriMapper”>
…
</nav:UriMapper>
</navigation:Frame.Resource>
After the change:
The Frame control has a property named UriMapper that takes a UriMapperBase:
public static readonly DependencyProperty UriMapperProperty;
public UriMapperBase UriMapper { get; set; }
13
Now, you can explicitly declare and specify a UriMapper, for example by binding to a
resource:
<navigation:Frame UriMapper=”{StaticResource uriMapper}” …>
</navigation:Frame>
Or, you can specify it directly:
<navigation:Frame …>
<navigation:Frame.UriMapper>
<nav:UriMapper>
…
</nav:UriMapper>
</navigation:Frame.UriMapper>
</navigation:Frame>
The API for UriMapper itself is unchanged.
3.19 Effects Files (.ps) can no longer be loaded as
Content
In Silverlight 3 Beta, effects files (pixel shaders) could be packaged as ‘Content’ or
as ‘Resource’ (Build Action = Content or Resource in the Visual Studio Properties
window). Silverlight now only supports effects files packaged as Resource. (There is
no change to the built-in DropShadow and Blur effects.)
To use a PS file, set its build action in Visual Studio to "Resource" and access it via
an assembly URI of the form "<assemblyName>;component/<filename>.ps". The
following shows an example of the SilverlightCustomEffect application loading
GrayScaleEffect.fx.ps:
pshader = new PixelShader() { UriSource = new
Uri("/SilverlightCustomEffect;component/GrayScaleEffect.fx.ps",
UriKind.Relative) };
3.20 WritableBitmap constructor parameter removed
The PixelFormat parameter for the WritableBitmap constructor has been removed:
public WriteableBitmap(int pixelWidth, int pixelHeight, PixelFormat format);
The only supported PixelFormat is now Pbgra32.
Similarly, the PixelFormat and PixelFormats type has been removed.
14
3.21 RenderOptions.TextRenderingOptions is now
TextOptions.TextHintingMode
Prior to this change:
public static class RenderOptions {
public static DependencyProperty TextRenderingMode
TextRenderingModeProperty;
}
public enum TextRenderingMode {
Default = 0,
RenderForAnimation = 1
}
After the change:
public static class TextOptions {
public static DependencyProperty TextHintingMode TextHintingModeProperty;
}
public enum TextHintingMode {
Fixed = 0,
Animated = 1
}
3.22 Transparent platform extensions are not hosted
on Microsoft.com
Transparent platform extensions will not be hosted on Microsoft.com. Instead they
will be hosted by default on the application’s site of origin. Application developers
can override this setting by editing the assembly-to-extension mapping file
(<assemblyShortName>.extmap.xml) located with the assembly.
3.23 Out-of-browser API name changes
Change to the Detach method in the System.Windows.Application type.
Signature
From
To
public bool Detach();
public bool Install();
public bool RunningOffline;
public bool RunningOutOfBrowser;
public event EventHandler
ExecutionStateChanged;
public event EventHandler
InstallStateChanged;
Changes to the ExecutionStates enumeration.
15
Signature
From
To
public enum ExecutionStates
{
RunningOnline,
Detaching,
Detached,
DetachedUpdatesAvailable,
DetachFailed
}
public enum InstallState
{
NotInstalled,
Installing,
Installed,
(removed, see below)
InstallFailed
}
Change to the ApplicationIdentity property in the Deployment element of the
application manifest (AppManifest.xaml).
From
To
XAML
<Deployment.ApplicationIdentity
…
<Deployment.OutOfBrowserSettings
…
Signature
public ApplicationIdentity
ApplicationIdentity;
public OutOfBrowserSettings
OutOfBrowserSettings ;
Moved ApplicationIdentity.Title to OutOfBrowserSettings.WindowSettings.Title.
XAML
From
To
<ApplicationIdentity
<OutOfBrowserSettings
ShortName=”…”>
ShortName=”…”
Title=”…”
>
<OutOfBrowserSettings.WindowSettings>
<WindowSettings Title=”…”
/>
<OutOfBrowserSettings.WindowSettings
/>
3.24 ExecutionStates.DetachedUpdatesAvailable is
removed
The ExecutionStates.DetachedUpdatesAvailable value has been removed from the
ExecutionStates enum (which is now the InstallState enum). Consider instead using
one of the following new APIs:


Application.CheckAndDownloadUpdateAsync() method
Application.CheckAndDownloadUpdateCompleted event
16


CheckAndDownloadUpdateCompletedEventArgs class
CheckAndDownloadUpdateCompletedEventArgs.UpdateAvailable property
3.25 Icon.Size type change and <Icon Size=”…”>
format changed
This type is typically used inside appmanifest.xaml to specify icon information for
out-of-browser applications. Changes affect both XAML and programmatic usage:



The Icon.Size property has changed from type string to type Size.
Values “small”, “medium”, and “large” are no longer accepted for Icon.Size
The XAML format is now the same as other properties of type Size. For
example, “16,16” instead of “16x16”.
Icon sizes are now validated. Valid icon sizes are “16,16”; "32,32"; "48,48";
"128,128"; "256,256"; "512,512".

Example:
Before:
<Icon Size="16x16">16.png</Icon>
<Icon Size="32x32">32.png</Icon>
<Icon Size="48x48">48.png</Icon>
<Icon Size="128x128">128.png</Icon>
After:
<Icon Size="16,16">16.png</Icon>
<Icon Size="32,32">32.png</Icon>
<Icon Size="48,48">48.png</Icon>
<Icon Size="128,128">128.png</Icon>
3.26
XmlConvert.IsNCNameSurrogatePair() and
IsStartNCNameSurrogatePair() have been
removed
The following methods have been removed:
class XmlConvert {
public static bool IsNCNameSurrogatePair(char lowChar, char highChar);
public static bool IsStartNCNameSurrogatePair(char lowChar, char highChar);
}
3.27 SaveFileDialog.File ->
SaveFileDialog.SafeFileName
The SaveFileDialog.File property has been removed. It has been replaced with the
SaveFileDialog.SafeFileName property:
17
public String SafeFileName { get; }
A String that only contains the file name for the selected file. The default is
Empty, which is also the value when either no file is selected or a directory is
selected.
3.28 WriteableBitmap[] is now
WritableBitmap.Pixels[]
The indexer on the WriteableBitmap class has been replaced with the Pixels
property:
public sealed class WriteableBitmap: BitmapSource {
public int this[int index] { get; set; }
public int[] Pixels { get; }
}
In typical usage:
myBitmap[index] = pixel;
becomes:
myBitmap.Pixels[index] = pixel;
3.29 WriteableBitmap.Lock() and Unlock() have been
removed; calling Invalidate() is now required
In Silverlight 3 beta, one had to call Lock() before modifying pixels and Unlock()
afterwards. Those calls are now unnecessary, instead one calls Invalidate() after
modifications are complete. E.g.:
myBitmap.Lock();
… modify pixels …
myBitmap.Unlock();
Becomes:
… modify pixels …
myBitmap.Invalidate();
4 Breaking Changes since Silverlight 2
The changes described in this section could potentially break Silverlight 2
applications. Many of these changes are actually bug fixes; nevertheless, if your
Silverlight 2 application employed workarounds for these bugs, it is possible that you
will have to remove these workarounds for your application to work correctly.
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4.1 System.Web.Silverlight.dll has been removed from
the SDK
The ASP.NET Silverlight and MediaPlayer controls have been removed from the
Silverlight 3 SDK. These are contained in a server assembly named
System.Web.Silverlight.dll that typically gets copied to the test Web site’s BIN folder.
<asp:silverlight ../>
<asp:mediaplayer ../>
Existing Silverlight 2 web sites will continue to work as they have the
System.Web.Silverlight assembly in their Web application’s BIN folder (even if the
Silverlight 2 SDK is uninstalled).
When upgrading existing projects to Silverlight 3, in most cases, you should replace
these controls with the equivalent <object> tag. For <asp:silverlight>, that is:
<div id="silverlightControlHost">
<object data="data:application/x-silverlight-2,"
type="application/x-silverlight-2" width="100%" height="100%">
<param name="source" value="{XAP_FILE}"/>
<param name="onerror" value="onSilverlightError" />
<param name="background" value="white" />
<param name="minRuntimeVersion" value="{BUILD}" />
<param name="autoUpgrade" value="true" />
<a
href="http://go.microsoft.com/fwlink/?LinkID=149156&v={BUILD}" style="textdecoration: none;">
<img src="http://go.microsoft.com/fwlink/?LinkId=108181"
alt="Get Microsoft Silverlight" style="border-style: none"/>
</a>
</object><iframe id="_sl_historyFrame"
style='visibility:hidden;height:0;width:0;border:0px'></iframe></div>
Existing Silverlight applications will continue to have the System.Web.Silverlight
assembly in their Web application’s BIN folder, even if the Silverlight 2 SDK is
uninstalled. Therefore upgrading to Silverlight 3 SDK will not remove this local
assembly and applications should continue to work. Notionally, a developer will set
the relevant version flag for Silverlight 3.


In the client, the older fwlinks rendered should now point to Silverlight 3.
Developers who added the System.Web.Silverlight assembly to the GAC
would have to manually remove it from the GAC per the install.
Developers creating new applications will want to use the latest templates that
contain the OBJECT tag and other markup.

Developers ‘could’ add the System.Web.Silverlight assembly manually and
use the server controls. However, these controls will not provide the latest
installation logic, or be able to render iframes for Silverlight history support
for example.
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4.2 Silverlight Applications now respond to Browser
Zoom
Silverlight applications (old and new) will have the opportunity to respond to Browser
Zoom depending on their current behavior. Silverlight applications will now zoom by
default if the application does not handle the Resized event. To the application,
zooming is equivalent to a RenderTransform = new ScaleTransform() being applied
to the imaginary parent of the root element.
Applications may customize this behavior by using the following new APIs:


System.Windows.Interop.Content's Zoomed event and ZoomFactor property.
(Content class is usually used as App.Current.Host.Content)
The EnableAutoZoom parameter on the Silverlight plugin
4.3 Popup Tab key Change
In Silverlight 2 if you have focus inside a popup and you press the TAB key, focus
leaves Silverlight entirely and goes to the browser; ignoring other tab stops within
the popup. The new and correct behavior in Silverlight 3 is to tab around inside the
popup first. If you want the old behavior you can set TabNavigation=”Cycle” on
the root of your popup.
4.4 ComboBox Popup Clipping Fixed
In Silverlight 2 if there is a vertical scrollbar in the ComboBox popup, and the popup
is wider than the ComboBox itself, the popup is too narrow by the width of the
scrollbar:
If you worked around this Silverilght 2 bug by artificially increasing the size of the
ComboBox items, in Silverlight 3 there will be extra space and you may want to
remove your workaround.
20
4.5 Silverlight always redraws Popups when
PopupRenderTransform changes
In Silverlight 2, Silverlight did not always redraw popups when
Popup.RenderTransform was changed. This has been fixed in Silverlight 3.
4.6 ContentPresenter.Content = "string" no longer
changes the ContentTemplate property
Previously, if you set ContentPresenter.Content = string, and then queried
ContentPresenter.ContentTemplate you would see a non-null value, the template
used to display the string. Now, setting ContentPresenter.Content = string no longer
changes the ContentTemplate property. This change was done so that
ContentPresenter.Content could not be set again after it has been set to string.
Note that this is ContentPresenter, not ContentControl. ContentPresenter is
typically used only inside control templates like so:
<ContentPresenter
Content="{TemplateBinding Content}"
ContentTemplate="{TemplateBinding ContentTemplate}"
HorizontalAlignment="{TemplateBinding
HorizontalContentAlignment}"
VerticalAlignment="{TemplateBinding
VerticalContentAlignment}"
Margin="{TemplateBinding Padding}"/>
4.7 ContentControl now ignores Content when using
an empty ContentTemplate
In Silverlight 2, if you give a ContentControl (such as Button) an empty
ContentTemplate, the control will ignore the template and displays the content
anyway using a ContentPresenter. For example, the following displays “ABC” in
Silverlight 2:
<ContentControl Content="ABC">
<ContentControl.ContentTemplate>
<DataTemplate></DataTemplate>
</ContentControl.ContentTemplate>
</ContentControl>
This has been fixed in Silverlight 3 and so the previous code now displays no
content.
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4.8 Setting ContentControl.Content does not cause
unnecessary OnApplyTemplate calls
In Silverlight 2, setting ContentControl.Content will call OnApplyTemplate every
time, even if ContentControl.ControlTemplate has been set. In Silverlight 3,
OnApplyTemplate will only be called the first time if ContentControl.ControlTemplate
has been set.
4.9 ComboBox and ContentControl now displays
strings rather than numbers when ItemsSource is
set to enum with typeconverter
In Silverlight 2, if you put enums into a ComboBox (its ItemsSource property), the
ComboBox will display the numeric value of the enum rather than the name of the
enum. For example:
enum MyEnum { First, Second, Third }
…
MyComboBox.ItemsSource = new MyEnum[] { MyEnum.First };
Displays "1” instead of "First". This has been fixed in Silverlight 3 so now the string
value of the enum is displayed.
4.10 ComboBox with no selected item takes an extra
keystroke to select second item
In Silverlight 2, when you open a ComboBox that has no selected item, the first item
in the list is treated as having focus (even though it is not selected), so the first
down arrow key moves both focus and selection to the second item. In Silverlight 3,
when that ComboBox is opened, the first item is not considered focused. The first
keydown moves selection and focus to the first item, and the second keydown moves
selection and focus to the second item.
4.11 HorizontalScrollBarVisibility and
VerticalScrollBarVisibility can now be set in a style
for ComboBox and ListBox
In Silverlight 2, these properties were set locally in the constructor, overriding any
value from the style. This has been fixed.
4.12 ListBoxItem.HorizontalContentAlignment is now
respected
In Silverlight 2, when using the default template for a ListBoxItem, the
HorizontalContentAlignment was ignored. This has been fixed.
4.13 ListBoxItem.Style now takes precedence over
ListBox.ItemContainerStyle
In Silverlight 2, if you set ListBoxItem.Style and then later (in code) set
ListBox.ItemContainerStyle, that would erroneously override the ListBoxItem.Style
you set earlier. This has been fixed.
22
4.14 Tabbing inside a ListBox now moves focus to next
control rather than next ListBox Item
In Silverlight 2, pressing TAB when focus is inside a ListBox moves to the next
ListBox item, rather than moving focus to the next control. Now the tabbing
behavior is consistent with other platforms.
4.15 Removed TemplatePart declarations from
PasswordBox/TextBox
For Silverilght 2, PasswordBox and TextBox had a number of [TemplatePart]
attributes describing parts the control did not actually have. These attributes have
been removed in Silverlight 3.
4.16 TextAlignment in TextBox now works relative to
the document instead of the TextBox
In Silverlight 2, text in TextBox did not center based upon the "document", but
based upon the width property of the TextBox, This caused center rendering to be
incorrect. For example, suppose that you start with centered text like this:
In Silverlight 2, if you type a long string, the TextBox looks like the following:
In Silverlight 3, this behavior was corrected. The correct behavior is for "ABC" to be
centered for the entire document, not the center of the visible portion of the
document. This change does not affect the overall size of the TextBox, and if the
user needs to, they can scroll the viewport to see the centered text. Nevertheless, if
you counted on the previous behavior, you may want to adjust your application.
4.17 Default colors for read-only TextBoxes have
changed
In Silverlight 2, read-only TextBoxes looked almost identical to editable text boxes.
23
4.18 ENTER key will now respects Button.ClickMode
which defaults to Release (KeyUp)
If the application changes ClickMode to Press, the click handler will not be able to
execute code that causes reentrancy. (Examples of code that could cause reentrancy
include OpenFileDialog and SaveFileDialog.)
4.19 Slider control's hit test area now matches what is
visible
In Silverlight 2, if you made the slider really tall, you could click in an area that does
not look like it is part of the slider, even though it is.
4.20 Malformed URLs inside clientaccesspolicy.xml
now cause that URL to be ignored, not the rest of
the file
In Silverlight 2, an invalid URL caused the remainder of the clientaccesspolicy.xml to
be ignored. This has been fixed.
4.21 Bug fix where changing Opacity did not always
redraw
In certain circumstances, Silverlight 2 would not redraw content when Opacity was
changed. This has been fixed.
4.22 DataBinding requires property setter to be public
Silverlight data binding generally requires properties and types to be public. In
Silverlight 2, there was a bug where a property with a public getter but a private
setter could be data bound to. This has been fixed.
4.23 Changing Binding.Path after SetBinding() is not
allowed
In Silverlight 2, it's possible to set the Binding.Path programmatically after using that
Binding in a SetBinding call, but before DataContext is set, eg:
Binding binding = new Binding();
myElement.SetBinding(HeightProperty, binding);
binding.Path = new PropertyPath("propertyname");
myElement.DataContext = …;
In Silverlight 3, once SetBinding has been called, the Path property may no longer be
changed, so the above code needs to be changed to:
Binding binding = new Binding();
binding.Path = new PropertyPath("propertyname");
myElement.SetBinding(HeightProperty, binding);
myElement.DataContext = …;
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If Path is changed after SetBinding() is called, the Silverlight 3 behavior depends on
what version of Silverlight the application was compiled against. If compiled against
Silverlight 3, setting Path after SetBinding() will throw an exception. However, to
reduce the chance of breaking Silverlight 2 applications, if the .xap is built against
Silverlight 2 setting Path after SetBinding() will be silently ignored and the old Path
will be used (see also discussion of "quirks mode" in section 5).
5 Upgrade Breaking Changes
The Silverlight team wanted to fix a number of Silverlight 2 bugs in Silverlight 3.
However, by fixing some of these bugs, it is possible that some existing Silverlight 2
applications will be broken. In order to avoid this, Silverlight developers made these
potentially problematic changes “quirk mode changes”. A quirk mode change is one
that the Silverlight 3 runtime will not enforce if the runtime detects that the
application being run was designed for Silverlight 2. In this way, Silverlight 3 is made
“bug compatible” with Silverlight 2 when a Silverlight 2 application is being run.
However, these changes will impact you if you recompile your application for
Silverlight 3.
As shown by the following illustration, if the RuntimeVersion for your application
specifies Silverlight 2, the runtime runs in "quirks mode". When in quirks mode, the
runtime falls back to the Silverlight 2 behavior associated with quirks mode changes.
From the illustration, you can see that the Silverlight 3 runtime detects whether the
application was designed for Silverlight 2 by using the RuntimeVersion. The
RuntimeVersion is set as an attribute inside the .xap’s AppManifest.xaml:
<Deployment xmlns="http://schemas.microsoft.com/client/2007/deployment"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
EntryPointAssembly="ElevatorSilverlight"
EntryPointType="ElevatorSilverlight.App"
RuntimeVersion="2.0.31005.0">
<Deployment.Parts>
<AssemblyPart x:Name="ElevatorSilverlight" Source="ElevatorSilverlight.dll" />
</Deployment.Parts>
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</Deployment>
RuntimeVersion reflects the build of Silverlight that was on the developer’s
machine when the application was compiled.
5.1 OpenFileDialog.ShowDialog() can now only be
opened from a user initiated event
For security reasons, OpenFileDialog.ShowDialog() may only be called during a
user initiated event (MouseLeftButtonDown/Up and KeyDown/Up) or derived user
event like clicking a button or checking a check box. This makes Silverlight behave
in the same way as other major browsers and plug-ins.
5.2 Tabbing processing and associated callbacks
changed from asynchronous to synchronous
In Silverlight 2, there was a bug associated with tabbing over the last control on the
page. As a side effect of fixing this bug, the tabbing processing and associated
callbacks, like the GotFocus event, were changed from asynchronous to
synchronous. (Where "asynchronous" really means PostMessage. It happens on the
same thread after the current message has been processed.) This is a breaking
change because during an asynchronous event in Silverlight, you cannot call into the
HTML DOM. This is the Silverlight version of WPF's unexpected reentrancy guard. In
quirks mode, applications continue to get asynchronous tab processing that does not
work very well for the last control on the page.
5.3 Mouse events inside a Popup now give positions
relative to the pop-up not the entire application
Suppose you have an element inside a pop-up that listens to mouse events:
[xaml]
<Popup>
<Border Name="border"
MouseLeftButtonDown="OnMouseLeftButtonDown"/>
</Popup>
[c#]
void OnMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
…
e.GetPosition(border) ...
}
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In Silverlight 2, the coordinates from MouseButtonEventArgs.GetPosition will be
relative to the entire Silverlight plug-in, even though the application asked for
coordinates relative to the border control (the parameter to GetPosition is supposed
to indicate the frame of reference). This has been fixed in Silverlight 3.
5.4 Popup can now only have one parent
In Silverlight 2, under certain circumstances a Popup can actually have two parents.
Silverlight 3 allows only a single parent for Popup.
5.5 Namescopes inside Popup now work correctly
Silverlight 2 had several bugs where named items inside a Popup were put in the
wrong namescope when Popup.Child was its own namescope (for example, child was
created with XamlReader.Load). This resulted in FindName() and
Storyboard.TargetName finding elements that should not have been found (because
Silverlight looked in the wrong name scope), and not finding elements that should be
found. In some cases FindName() would find elements that had been removed from
the tree. This has been fixed in Silverlight 3. The correct name scope behavior is
when Popup is added to the live tree, and Popup.Child is not a namescope owner,
the popup children become part of the popup parent's name scope. Otherwise,
popup’s children live in a namescope attached to Popup.Child.
5.6 FindElementsInHostCoordinates now searches
Popup's
In Silverlight 2, FindElementsInHostCoordinates would not look inside Popup’s. This
has been fixed.
5.7 Removed extra events associated with replacing
Item in ItemsControl
In Silverlight 2, replacing items in ItemsControl generates three events: Remove,
Add, and Replace. This is not compatible with WPF and it is hard to code against.
When you receive the remove and add events, you do not know if it is really a
replace that is about to follow. In Silverlight 3, only the Replace event occurs.
5.8 ScrollViewer now clamps scrollbar positions to
ScrollableWidth/ScrollableHeight
As a result, the Width and Height of content inside a ScrollViewer will be zero until
the layout pass is complete.
5.9 Rectangle and Ellipse now appear when Stretch is
set and Height and/or Width are not set
In Silverlight 2, if Stretch != UniformToFill and Height or Width was not set on a
Rectangle or Ellipse within a ContentControl, then the object was not rendered.
In Silverlight 3, if the Stretch property of a Rectangle or Ellipse is other than
None, the object will be rendered.
27
5.10 Width of TextBlock, TextBox, and PasswordBox
now rounded up
In Silverlight 2, if you let PasswordBox, TextBlock and TextBox autosize
themselves, they will truncate the final character if the natural width of the text is
not a whole number and the fractional part of that is less than .5. For example, text
which measures to 96.34 units wide will get rounded down to 96.00, and the
TextBlock does not have enough space to display the text. Now the width is
rounded up but this could potentially affect the layout of your applications.
5.11 textblock.FontFamily = null throws
ArgumentNullException
In Silverlight 2, textblock.FontFamily = null throws a NullRefException, now it
throws ArgumentNullException.
5.12 Spaces no longer rendered between Run elements
within template
Inside a template, Silverlight 2 implicitly inserted a space between elements, so
<TextBlock><Run Text="Hel"/><Run Text="lo"/></TextBlock> would have a space
between "Hel” and “lo”. In Silverlight 3, this space is no longer rendered.
5.13 RadioButton.GroupName now searches outside
template for RadioButtons
In Silverlight 2, if you use RadioButton.GroupName inside a template, Silverlight
only looks inside that template for RadioButtons with the same group name. This is
different from WPF and makes it difficult to perform a lot of useful scenarios. So in
Silverlight 3, the RadioButton searches outside the template as well.
5.14 ComboBox content now gets
IsHitTestVisible="false"
In Silverlight 2, the selected item inside a ComboBox will receive mouse events.
This interfered with ComboBox displaying correct visuals for mouse over state, so
ComboBox will now set IsHitTestVisible="false" on the ContentPresenter inside its
control template. ComboBox itself continues to get mouse events.
5.15 TextBox now respects the Opacity property
In Silverlight 2, the Opacity property was ignored (always treated as 1). This has
been fixed.
28
5.16 FrameworkElementAutomationPeer ctor with null
parameter throws NullReferenceException
In Silverlight 2, the FrameworkElementAutomationPeer ctor with a null
parameter threw a NullReferenceException. Now this throws
ArgumentNullException.
5.17 HyperlinkButton now navigates the entire
window and not just the IFRAME that Silverlight is
in
In Silverlight 2, HyperlinkButton behaved inconsistently across browsers. In
Internet Explorer, HyperlinkButton navigated the entire browser, not just the
current IFrame.
In other browsers, HyperlinkButton navigates only the current IFrame, which is
consistent with HTML behavior. In Silverlight 3 Beta, the behavior inside Internet
Explorer was changed to match the behavior in other browsers.
5.18 Correct base URI used when Silverlight v2+
application does not have XAP file extension
With the Silverlight 2 plug-in, if you renamed a .xap file to have a different
extension, Silverlight erroneously thought the application was designed for Silverlight
1, and Silverlight ran it in version 1 compat mode. One impact was the base URI
was considered to be the HTML page, not the (renamed) .xap. Another impact was
that the default font was different from a .xap. This has been fixed.
5.19 Application.Current.Host.Source now returns an
absolute URL even when .xap URL has a query
string
In Silverlight 2, if the URL the .xap was loaded from contained a query string,
Application.Current.Host.Source could return a relative URL. In Silverlight 3, this has
been fixed and Application.Current.Host.Source always returns an absolute URL. The
URL of the .xap is typically specified as a <param> within the <object> tag, the
following is an example of a .xap URL with a query string:
<param name="source" value="Bin/Debug/bug24857.xap?a=b"/>
5.20 ResourceDictionary enum bug fixed
In Silverlight 2, if you put an enum into a ResourceDictionary and take it out
again, you get back an object of type Integer32 rather than something of the
expected enum type. This has been fixed for Silverlight 3.
29
5.21 ReadOnlyObservableCollection moved from
System.Windows.Controls.Data.dll to
System.Windows.dll
The ReadOnlyObservableCollection class has been moved into
System.Windows.dll so that other APIs in System.Windows.dll can use it. In order
to minimize download size impact, some uncommonly used methods were removed.
Note that this will not affect applications compiled for Silverlight 2. If you use
ReadOnlyObservableCollection in Silverlight 2, your .xap file will contain a copy of
System.Windows.Controls.Data.dll. When Silverlight 3 Beta runs your .xap, it will
use the .xap's copy of System.Windows.Controls.Data.dll and that version of
ReadOnlyObservableCollection, not the version that ships in the
System.Windows.dll of Silverlight 3 Beta.
5.22 DataGridEndingEditEventArgs was removed from
the SDK
There was no event that returns this EventArgs, so it was removed.
5.23 PollingDuplexHttpBinding Changes
PollingDuplexHttpBinding now derives from HttpBinding instead of
BasicHttpBinding. PollingDuplexHttpBinding now uses SOAP 1.2 instead of 1.1.
As a result, Silverlight 3 PollingDuplexHttpBinding will not work with ASP.NET
servers running the Silverlight 2 version of
System.ServiceModel.PollingDuplex.dll.
5.24 Bug fix with removing event handlers
Normally, when one removes an event listener (-= in C#), they remove a particular
delegate for a particular event. Silverlight 2 ignored the event part – “foo.Bar -=
Baz” would remove all event listeners tied to the Baz method, including events other
than Bar. In Silverlight 3 this has been fixed.
5.25 Bug fix allowing <Cursors> instead of <Cursor>
In Silverlight 2, the following was allowed:
<DiscreteObjectKeyFrame.Value>
<Cursors>Hand</Cursors> <-------note plural
</DiscreteObjectKeyFrame.Value>
This was incorrect since the name of the type is Cursor not Cursors. Silverlight 3
only allows <Cursor>.
5.26 Custom attached properties in XAML require
xmlns are prefixed
In Silverlight 2, the following illegal XAML was accepted by Silverlight:
<local:MyControl MyControl.DesignerID="12" />
30
This has been fixed in Silverlight 3. The correct XAML uses an XML prefix on the
attached property:
<local:MyControl local:MyControl.DesignerID="12" />
5.27 Bug fix where subclass control could load wrong
resource
In Silverlight 2, under certain conditions, if class A is defined in one user assembly,
and markup inherits from class B in a different user code assembly,
Application.LoadComponent(A) will try to load XAML from B's assembly instead of A's
assembly. This has been fixed.
5.28 Bug fix where ValueConverter is not called when
leaf object on the path is null
Silverlight 2 data binding is inconsistent about how it handle nulls. If you specify
Path=a.b.c.d and a, b, or c is null, Silverlight 2 calls the ValueConverter. However, if
you specify Source=null, that does not call the value converter, even though it
logically means the same thing. Silverlight 3 will always call the value converter.
5.29 Thumb control now calculates drag relative to the
absolute position rather than relative to its parent
This is most noticeable if the parent element is moving as a result of the drag.
5.30 Setting Binding properties after SetBinding() no
longer supported
In Silverlight 2, it's possible to programmatically set various properties on Binding
between when SetBinding() is called but before DataContext is set, eg:
Binding binding = new Binding();
myElement.SetBinding(HeightProperty, binding);
binding.Foo = value;
myElement.DataContext = …;
Different properties had different behaviors in SL2:


Converter, ConverterParameter, ConverterCulture, NotifyOnValidationError,
and ValidatesOnExceptions properties would retroactively change the binding
established with SetBinding().
Mode and Source properties would be ignored (their values were copied when
SetBinding() was called)
Silverlight 3 throws an exception if these properties are changed after SetBinding() is
called. (Silverlight 2 will throw a similar exception if these properties are changed
after DataContext is set)
31
5.31 Child of a ContentPresenter can now only have
one parent
In Silverlight 2, under certain circumstances the content (child element) inside a
ContentPresenter can actually have two parents, because the content has been
added to a second ContentPresenter without removing it from the first
ContentPresenter. Silverlight 3 will throw an exception if an element is added to a
second parent without removing it from the first parent.
5.32 Relative URLs pointing to resources outside the
.xap are now relative to the .xap file not the HTML
page
Suppose the HTML page & the xap file are in different directories (e.g.
http://example.com/ and http://example.com/ClientBin/), and you have a relative
URL to a resource (eg images/foo.jpg) that is not contained within the xap file. SL2
would interpret that URL relative to the HTML page's location
(http://example.com/images/foo.jpg). In order to make it easier to move Silverlight
apps to different locations, Silverlight 3 interprets the URL relative to the .xap’s
location (http://example.com/ClientBin/images/foo.jpg).
<section 5 -- upgrade breaking changes/quirks mode>
5.33 Silverlight 3 automatically displays validation
errors
In Silverlight 2, the default control templates were not aware of validation errors. In
Silverlight 3, they are. Applications that display their own UI for validation errors
(typically by listening to FrameworkElement.BindingValidationError) can turn off the
built-in validation UI by re templating the affected control and removing the
ValidationStates VisualStateGroup. You can do this in Blend by right clicking on the
control, selecting “Edit Template” then "Edit a copy…", then give it a name, then go
to xaml view and remove the following from the <Style>:
<VisualStateGroup x:Name="ValidationStates">
<VisualState x:Name="Valid">
...
</VisualState>
<VisualState x:Name="InvalidUnfocused">
...
</VisualState>
<VisualState x:Name="InvalidFocused">
...
</VisualState>
</VisualStateGroup>
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5.34 Image.Source and ImageBrush.Source now
return null when not initialized
In Silverlight 2, getting Image/ImageBrush.Source before the property was set
would create an empty BitmapImage. In Silverlight 3, if the property has not been
set, it will return null. For example, if ImageBrush.Source has not been set, the
following line of code will return null in Silverlight 3:
elementWithImageBrush.Fill.GetValue(ImageBrush.ImageSourceProperty)
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